Tunneling effects in light-emitting diodes based on InGaN/AlGaN/GaN heterostructures with quantum wells

Electroluminescence Properties of InGaN/AlGaN/GaN Light Emitting Diodes with Quantum Wells

“…3 (see a method of measurements in [8]). The LEDs with MQWs have wider space charge width than ones with SQWs [2][3][4][5]7]; in both cases the width for green LEDs is wider than for blue ones. This fact corresponds to a low probability of tunnel effects in the LEDs with MQWs.…”

“…The maximum of this band is moving with the current J and voltage on the active layer U: hω max = eU+∆ (in the range = 2.1-2.3 eV). This band was described as a tunnel radiative recombination [4,5]. There is no tunnel band in blue LEDs with MQWs; in this case the blue line is moving with V.…”

“…Low currents could be understood as a tunnel component; tunnel currents in these LEDs play some role at J 3-4 orders of magnitude lower than that for SQWbased LEDs [2][3][4][5]7]; J(V) curves of SQW-based LEDs differed from MQW-based LEDs because of a wider active layer [1]. A good approximation of the J(V) curves for MQW LEDs was done when not only a series resistance R s at the linear part at higher J was taken into account, but also the quadratic part: J ( V-V 1 )…”

“…We have studied luminescence spectra of two groups of LED's based on structures with single InGaN quantum wells (SQWs, sent to Moscow University by Dr. S.Nakamura, Nichia Chemical Co.) and multiple quantum wells (MQWs, sent to Moscow University by Dr. M.Koike, Toyoda Gosei Co.) in a wide range of currents [2][3][4][5][6]. A model of radiative recombination in 2D-structures with band tails caused by potential fluctuations was successfully applied to describe the spectra [2][3][4]; tunnel radiative recombination was detected at low currents [5]. In this work spectra of blue and green LEDs with SQW and MQW active layers are compared and the model of recombination is analyzed.…”

The Emission Properties of Light Emitting Diodes using InGaN/AlGaN/GaN Multiple Quantum Wells

“…There is no additional band in the yellow-green region moving with the voltage at low currents. Such a band was described as a tunnel band in blue SQW LEDs [5] [6] [7]. The maxima of the spectra of the green LEDs move in the range h ω max = 2.2-2.45 eV, a wider range than in green SQW LEDs…”